Radioactive material handling and storage apparatus

ABSTRACT

Radioactive material handling and storage apparatus, including a storage block containing a bore for receiving a holder of a source of radioactive energy. The invention is characterized by the provision of means automatically operable upon insertion of the source holder in the bore to effect insertion of a protective closure member in the bore into engagement with the source holder, whereby the holder is shielded to prevent the escape of radiation from the bore.

United States Patent lnventor Daniel Lecuyer Domaine De Grandchamps, France Appl. No. 687,346 Filed Dec. 1, 1967 Patented Feb. 2, 1971 Assignee Societe A.G.S., Societe Anonyme Paris, France Priority Dec. 20, 1966 France 88,] 13/66 RADIOACTIVE MATERIAL HANDLING AND STORAGE APPARATUS 9 Claims, 13 Drawing Figs.

US. Cl 250/106, 250/108 Int. Cl G2lh 5/00, G2lp 5/02 [50] Field of Search 250/1065, 108

[56] References Cited UNITED STATES PATENTS 2,872,587 2/1959 Stein 250/108X 3,026,414 3/ l 962 Commins 250/ I 06.5 3,353,023 11/1967 Lowery et al. 250/lO6.5

Primary Examiner-Archie R. Borchel/t Attorney-Lawrence E. Laubscher ABSTRACT: Radioactive material handling and storage apparatus, including a storage block containing a bore for receiving a holder of a source of radioactive energy. The invention is characterized by the provision of means automatically operable upon insertion of the source holder in the bore to effect insertion of a protective closure member in the bore into engagement with the source holder, whereby the holder is shielded to prevent the escape of radiation from the bore.

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RADIOACTIVE MATERIAL HANDLING AND STORAGE APPARATUS It is well known in the prior art relating to containers for storing sources of radioactive energy. such as gamma radiography apparatus and the like. to provide means operable upon return of a source holder to its safety position in the storage channel for causing a protective block to be positioned in front of the source storage channel.

The known devices unfortunately have several inherent drawbacks. For example, in some cases the operator may forget to position the protective block in the safety position, whereupon undesirable radiations are produced that may injure the operator or other persons passing in front of the unprotected ejection channel.

Furthermore, most of these known apparatus do not indicate that the source holder has returned to its proper storage position, and it is quite possible that accidentally this source holder, or a part thereof, remains positioned outside the storage bore. Although some apparatus are equipped with a posting means showing that the rear of the source holder has returned to its position, this is generally not sufficient. It is the object of the present invention to obviate the disadvantages and drawbacks outlined hereinabove.

The primary object of the present invention is to provide closure means formed from heavy radiation-absorbing material, characterized in that, on the one hand, the removal thereof is manually controlled, while the closing thereof is automatic. More particularly, means are provided for assuring that the closure means is automatically returned to the safety position when the source holder has returned to its storage position.

According to a further object of the invention, means are provided for ascertaining that the entire source holder is in the storage position.

The means which assure the automatic safety closure of the bore and shielding of the radioactive source comprise a closing member laterally displaceable to a first position opposite the source holder, said member then being axially shiftable into the storage bore into contact with the source holder. The initial lateral movement of the closure member may be effected by rotational or translational movement of mechanical carriage means. In the first instance, a pair of parallel tubes are disposed on rocker means which are pivotable about a pivot shaft, one of these tubes being adapted to receive the closure member so as to allow for the further rotational movement of the rocker means to a position in which the empty second tube may receive the source holder from the storage means.

In accordance with a further object of the invention, the rotational movement of the rocker is obtained by means of a cam, said cam serving both to effect the lateral movement of the closure member and for subsequently axially displacing the latter within the storage channel. The means for effecting the axial movement of the closure member comprise an oscillating lever which is actuated by the cam.

In the preferred embodiment, the means for checking and ascertaining that the source holder is entirely in the storage position includes the closure member which serves as a feeler means, said closure member being in operative engagement with damping and signaling means.

Other objects and advantages of the present invention will become apparent from a study of the following specification, when viewed in the light of the accompanying drawing, in which:

FIG. 1 is a somewhat schematic top plan view of the apparatus, with certain parts removed;

FIG. 2 is a sectional view taken along line 11- of FIG. 1;

FIG. 3 is a sectional view taken along line IIIIII of FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 1,

FIG. 5 is a sectional view taken along line V-V of FIG. 4 showing the safety locking means, the late latter being, however, in the opening position in this case;

F IG. 6 is a detailed top plan view of the means for initiating the automatic closing of the closure means when the isotope is in the storage position;

FIG. 7 is a schematic electrical diagram showing the indicating means maintained in the normal position by the lever associated with the closure member;

FIGS. 8 to II are diagrammatic cross-sectional views of the apparatus described hereinbefore, showing the principal phases of the operation thereof; and

FIGS. 12 and I3 are diagrammatic end views of the two principal embodiments of the device as proposed by the present invention.

Referring now to the drawing, the gamma radiography apparatus includes a rectangular housing, having end walls 1 formed of an alloy or light weight metal, and sides 2 normally covered by hood means (not shown).

Within the housing is mounted a protective block 3 formed of a heavy metal (such as lead), said block containing a bore 7 for receiving an isotope source 4 secured to the end of a cable 5. The cable is shielded by an outer conduit 6 that prevents radiation from leaking rearwardly from the housing. At its free forward end, the bore 7 is closed by .a cylindrical closure member 8 also formed of a heavy shielding metal, such as lead.

At the forward end of the block 3 is mounted rocker means 9 which oscillates about and which carries at its free end a pair of horizontal parallel tubes 10 and 11 (FIGS. 1 and 2).

In order to remove the source holder 4 from the apparatus, it is necessary to cause the closure member 8 to be withdrawn within the tube 10 until it no longer contacts the block 3, whereupon the rocker 9 is pivoted about axis 9a so as to position the empty second tube 11 opposite the channel 7, which tube is then adapted to receive the source holder 4 for subsequent conduction to the ejection conduit 12.

These two movements are controlled (FIGS. 2 and 3) by means of a circular cam 13 that is mounted for oscillation about axis 13a and carries a laterally projecting pin 14 that ex tends within a slot 15 contained in a doublearmed lever 16 that pivots at its lower end about pivot :axis 17. Referring to FIG. 2, when cam 13 is rotated in the clockwise direction, lever 16 is pivoted about shaft 17 (by the cooperation between pin 14 and slot 15) in the counter clockwise direction from the initial position illustrated in solid lines. During this pivotal movement of the double-armed lever 16, the closure member 8 is withdrawn from the bore 7 into the tube 10 by the cooperation between the lateral lugs 16a on the member 8 with the corresponding vertical slots contained in the arms of lever 16 as shown in FIGS. 2 and 3.

The cam 13 also contains a slot 18 which receives a pin 19 integral with the rocker 9. This slot is centered at the ends thereof on the axis of rotation of the cam in a manner such that, during the withdrawal of the closure member 8 as described above, the cam will not act upon the finger 19. Upon further rotation of the cam in the clockwise direction, the slot 18 acts upon the finger l9, integral with the rocker 9, causing it to pivot about shaft 9a and to bring the empty tube 11 into the ejection position at the location previously occupied by the tube 10 (i.e., opposite the bore 7 in block 3). The empty tube 11 is thus positioned to receive the radioactive source 4 from the bore 7.

The rotational movement of the cam 13 is controlled by a shaft 20 upon which is secured a pinion 21 that meshes with a rack 22. To remove the closure member 8 from the bore 7, knob 23 and shaft 24 are displaced to the right, so that stop 25 (FIG. 4) engages surface 26 to shift tube 27 and rack 22 to the right against both the force of spring 30 and also the damping effect caused by the movement of piston 28 in fluid cylinder 29. Rectilinear movement of rack 22 to the right causes clockwise rotation of pinion 21 and spindle 20, thereby rotating cam 13 in the clockwise direction as described above. The spring 30 has thus been compressed as a result of the righthand movement of tube 27. Cam l3 continues to rotate until an end position is reached in which a pawl 31 (FIG. 2) engages a notch 32 on the cam periphery, said pawl being connected with a rod 33 that is biased to the left by a spring 34. The cam is now latched in position by the pawl 31, and holder 4 may be displaced into the empty tube 11 by shifting cable 5 to the left.

In accordance with an important feature of the invention. means are provided for automatically releasing the pawl latch 31 as the source holder 4 is returned to its initial storage position within bore 7. To this end, a knob 35 (FIG. 6) is provided on the cable 6 for engagement with the blade 36 of a springbiased lever 39 that pivots about shaft 37 on support 38. Upon pivotal movement of lever 39 in the counterclockwise direction, escapement means 40 carried thereby is shifted to the right to the position shown in phantom, thereby shifting also rod 33 to the right, whereby pawl 31 is pivoted to the released position shown in phantom in FIG. 2. Owing to the restoring force of compressed spring 30, tube 27 is shifted to the left to drive pinion 21 and cam 13 in the counterclockwise direction, whereupon rocker 8 is pivoted downwardly to the position shown in phantom in FIGS. 2 and 3, an and doublearmed lever 16 is pivoted in the clockwise direction to effect insertion of closure member 8 within the bore 7 into contiguous engagement with the adjacent end of source holder 4.

In order to avoid any involuntary opening of the closure means 8, lock means are provided including a small plate 41 having a pair of arms terminating in lug portions 42,43, respectively, in operative engagement with an annular flange 44 secured to the tube 27 (FIG. 1). This small plate, which is shown particularly in FIG. is mounted on a support 45 for pivotal movement about pivot shaft 46. A cam 47 is rigidly attached to a shaft 48 mounted on the right-hand end wall 1 of the apparatus, said shaft being rotatable by a safety key 49 to position lugs 42,43 against the stop 44 of the tube 27, thereby preventing the knob 23 from being actuated before the key 49 has been properly operated.

FIG. 7 illustrates schematically the signaling device by means of which it is possible to determine the presence and the length of the source holder. In the position shown in the figure, the holder 4 is in the initial storage position and closure member 8 has been applied against the left-hand extremity thereof. In this position h the double lever 16 is shown in full lines. The end of this lever bears against a small roller 50 carried by a U-bolt which supports a small spindle 52 whose free end is articulated at 53 on a movable switch contact 54 that pivots at 55. The free end of the movable contact is adapted to engage alternately the stationary contacts 56 and 57 which are part of green and red light branch circuits, respectively. The two circuits are connected, via flasher means 58, with an alternating current or direct-current voltage source 59. The connection between the flashing device and the voltage source is controlled by means of a switch 60. Finally, a return spring 61 normally biases contact 54 toward engagement with the red light contact 57. Consequently, the green light branch is closed only if the lever 16 is in the illustrated position placing closure member 8 in contact with the source holder 4, the.

latter having returned to the safety position thereof and having its normal length.

For any other position of the closure member 8, the double lever 16 is positioned either to the right or to the left of the position shown in the figure in full lines, and at that instant, the switch contact 54 is returned to the contact 57 by means of the spring 61. Since the switch 60 is in the normally closed condition, the red light will blink. The extreme position of the lever 16 to the right and to the left of the position corresponding to the safety position thereof are shown in dotted lines. When the lever is placed to the left, as has previously been described, the holder 4 is withdrawn and consequently is no longer in the safety position. Any position of the lever 16 to the right of the safety position corresponds to a reduction in the length of the source holder (i.e., the left-hand extremity terminates at the position 4). This serves as an indication of the fact thata part of the source holder has not returned to the initial position and is somewhere at the outside. At that moment, the red blinker light shows that there is danger. Any other warning device, such as an acoustical alarm, could, of course, also be suitable. The blinker device is advantageous since it is noticed more readily and further saves current.

FIGS. 8 to 11 illustrate schematically the different phases of operation of the device, the position of the cam being illustrated schematically with a circle.

The position shown in FIG. 8 is the ejection position, the

tube 10 containing the closure member 8 being raised and the has not returned completely within the bore 7. It is seen from this figure, in fact, that the source holder has reduced dimensions. At that instant, the closure member 8 which plays the role of a feeler penetrates more deeply toward the right thereby operating either the electrical contact of an alarm system as described above, or a mechanical signal.

It should also be noted that the penetration of the closure member 8 may be damped by piston means (not shown).

As has been set forth hereinabove, instead of bringing about displacement of the tubes 10 and 11 by a rotational movement, one could attain the same effect also by a translational movement. FIGS. 12 and 13 illustrate, respectively, in a schematic manner the provision which has just been described hereinbefore and which is based on the rotation, as seen in FIG. 13 by means of a cage 9, and the provision based on the translation, as shown in FIG. 12. In the latter case, the tube 10 and the tube 11 are supported by a vertically reciprocable housing 9a whose ends are formed of plates.

While in accordance with the provisions of the Patent Statutes, the preferred form and embodiments of the invention now known to me have been illustrated and described, it will be apparent to those skilled in the art that changes may be made without deviating from the invention set forth in the following claims.

I claim:

I. Apparatus for handling and storing a source of radioactive energy, comprising:

a storage block containing a bore for receiving a holder of the radioactive source;

a closure member initially mounted in the free end of the bore to close the bore and thereby shield the source holder to prevent radiation from escaping the bore;

first means for removing said closure member from the.

bore, said first means including means for axially displacing said closure member to a withdrawn position directly opposite and spaced from the bore, and laterally displaceable means for effecting lateral movement of said closure member from said withdrawn position to a position remote from the bore;

second means for removing the source holder from, and for returning the source holder to, the bore; and

means responsive to the return of the source holder into the bore for automatically operating said first means to reinsert the closure member into the bore. 2. Apparatus for handlingand storing a source of radioactive energy, comprising:

a storage block containing a bore for receiving a holder of the radioactive source;

a closure member initially mounted in the free end of the bore to close the bore and thereby shield the source holder to prevent radiation from escaping from the bore;

first means for removing said closure member from the bore, said first means including lever means for axially displacing said closure member to a withdrawn position directly opposite and spaced from the bore, and laterally displaceable means for effecting lateral movement of said closure member from said withdrawn position to a position remote from the bore;

second means for removing the source holder from and for returning the source holder to, the bore;

means responsive to the return of the source holder into the bore for automatically operating said first means to reinsert the closure member into the bore and in engagement with the adjacent end of the source holder; and

electrical indicator means operable by said lever only when said lever and the said adjacent end of the source holder are in their initial positions relative to said storage block, whereby an indication is afforded only when the entire source holder has been returned to its initial position in the bore.

3. Apparatus as defined in claim 1 wherein said laterally displaceable means includes pivotally movable rocker means.

4. Apparatus as defined in claim 1, wherein said laterally displaceable means includes a linearly shiftable carriage.

5. Apparatus as defined in claim 3, wherein said rocker means includes parallel first and second tubular members, said rocker means being pivotable between first and second positions in which said first and second tubular members are successively arranged colinearly opposite said bore for axially receiving said closure member and said source holder, respectively.

6. Apparatus as defined in claim 5, and further including cam means for pivoting said rocker means between said first and second positions.

7. Apparatus as defined in claim 6, wherein said means for axially displacing said closure member comprises lever means pivotally operable by said cam means when said rocker means is in the first position, whereby as said closure member is axially withdrawn from said bore, it is simultaneously axially inserted within said first tubular member.

8. Apparatus as defined in claim 7, wherein said means for automatically operating said first means to reinsert said clo sure member in said bore comprises;

spring means biasing said rocker means toward said first position for biasing said axially displaceable means in the direction returning the closure member within the bore; and

latch means for latching said cam means in the position in which the closure member is in the remote position relative to the bore;

said means responsive to the return of said source holder in said bore being operable to release said latch means, whereupon said closure member is successively shifted from said remote position to said withdrawn position, and from said withdrawn position to the shielding closure position within the bore.

9. Apparatus as defined in claim 7, and further including indicator means operable by said lever when said closure member is in a predetermined position of engagement with the source holder to indicate that the entire source holder has been returned to its initial position in the bore. 

2. Apparatus for handling and storing a source of radioactive energy, comprising: a storage block containing a bore for receiving a holder of the radioactive source; a closure member initially mounted in the free end of the bore to close the bore and thereby shield the source holder to prevent radiation from escaping from the bore; first means for removing said closure member from the bore, said first means including lever means for axially displacing said closure member to a withdrawn position directly opposite and spaced from the bore, and laterally displaceable means for effecting lateral movement of said closure member from said withdrawn position to a position remote from the bore; second means for removing the source holder from, and for returning the source holder to, the bore; means responsive to the return of the source holder into the bore for automatically operating said first means to reinsert the closure member into the bore and in engagement with the adjacent end of the source holder; and electrical indicator means operable by said lever only when said lever and the said adjacent end of the source holder are in their initial positions relative to said storage block, whereby an indication is afforded only when the entire source holder has been returned to its initial position in the bore.
 3. Apparatus as defined in claim 1 wherein said laterally displaceable means includes pivotally movable rocker means.
 4. Apparatus as defined in claim 1, wherein said laterally displaceable means includes a linearly shiftable carriage.
 5. Apparatus as defined in claim 3, wherein said rocker means includes parallel first and second tubular members, said rocker means being pivotable between first and second positions in which said first and second tubular members are successively arranged colinearly opposite said bore for axially receiving said closure member and said source holder, respectively.
 6. Apparatus as defined in claim 5, and further including cam means for pivoting said rocker means between said first and second positions.
 7. Apparatus as defined in claim 6, wherein said means for axially displacing said closure member comprises lever means pivotally operable by said cam means when said rocker means is in the first position, whereby as said closure member is axially withdrawn from said bore, it is simultaneously axially inserted within said first tubular member.
 8. Apparatus as defined in claim 7, wherein said means for automatically operating said first means to reinsert said closure member in said bore comprises; spring means biasing said rocker means toward said first position for biasing said axially displaceable means in the direction returning the closure member within the bore; and latch means for latching said cam means in the position in which the closure member is in the remote position relative to the bore; said means responsive to the return of said source holder in said bore being operable to release said latch means, whereupon said closure Member is successively shifted from said remote position to said withdrawn position, and from said withdrawn position to the shielding closure position within the bore.
 9. Apparatus as defined in claim 7, and further including indicator means operable by said lever when said closure member is in a predetermined position of engagement with the source holder to indicate that the entire source holder has been returned to its initial position in the bore. 